Policy and charging control (PCC) for NAT64 and DNS64

ABSTRACT

A mechanism for use by a subscription control node, one or more NAT64 nodes and/or DNS64 nodes to interact in a communications network with multiple user equipments (UEs) to control the UE usage of the NAT64 and/or DNS64 communications resources. The subscription control node includes subscription information for one or more of the UE(s), the subscription information for each UE including translation state usage information associated with one or more of the NAT64 nodes servicing the UE. The subscription control node collects translation state usage information from each NAT64 node, and identifies a set of one or more UE(s) exceeding a maximum translation state usage allocated to each of the multiple UEs based on the corresponding subscription information and the collected translation state usage information. The subscription information for the identified UEs is adjusted so the identified set of UE(s) meet the maximum translation state usage for each UE.

CROSS REFERENCE TO RELATED APPLICATION

This application is a 35 U.S.C. §371 national stage application of PCTInternational Application No. PCT/EP2011/074328, filed on 30 Dec. 2011,the disclosure of which is incorporated by reference herein in itsentirety. The above-referenced PCT International Application waspublished in the English language as International Publication No. WO2013/097910 A1 on 4 Jul. 2013.

TECHNICAL FIELD

The present invention relates to methods and apparatus for monitoringand controlling the user equipment usage of Network Address TranslationInternet Protocol version 6 to Internet Protocol version 4 (NAT64)and/or Domain Name System 64 (DNS64) communication resources in acommunication network. In particular, the present invention relates tomethods and apparatus for operating a subscriber control node, a NAT64node and/or a DNS64 node to interact with each other for monitoring andcontrolling the UE usage of the NAT64 and DNS64 communication resources.

BACKGROUND

Due to the Internet Protocol version 4 (IPv4) network address spacebecoming exhausted, communications network operators are moving todeploy Internet Protocol version 6 (IPv6) networks. The Third GenerationPartnership Project (3GPP) have defined standards for specifyingpossible migration techniques for operators when changing their mobilecore networks from IPv4 to IPv6. However, as the majority of mobile corenetworks, and other communication networks such as the Internet, arestill based on IPv4 addressing, the 3GPP have specified a NAT64 node fortranslating the UE traffic from IPv6 addresses to IPv4 addresses used bycurrent communications networks and Internet services.

A UE may comprise or represent any device used for communications.Examples of user equipment that may be used in certain embodiments ofthe described access networks are wireless devices such as mobilephones, terminals, smart phones, portable computing devices such as laptops, handheld devices, tablets, net-books, computers, personal digitalassistants and other wireless communication devices.

UEs attached to the mobile core network will use IPv6 addressing suchthat all the traffic to and from each UE is using IPv6 addresses. Inorder for the UE to access certain services in the Internet it will tryto resolve the IPv6 address of the service via a DNS64 node. The UEsends the uniform resource locator (URL) of the service to the DNS64node. The DNS64 node will try to resolve both IPv4 and IPv6 addressesfor the given URL. If an IPv6 address is returned then the UE simplyuses the native IPv6 connectivity for using the service. However, ifonly an IPv4 address is returned for the given URL, then the DNS64 nodewill synthesize an IPv6 address for the service. The synthesized IPv6address will hold the 32 bit IPv4 address of the resolved service in thehost part of the IPv6 address. The network part of the synthesized IPv6address will hold the so-called prefix64 of a NAT64 node, which willperform the address family translation for the connection. Thesynthesized IPv6 address is returned to the UE by the DNS64 node as areply to the URL resolve request. As a result, the UE will initiatecommunication to the service by using the synthesized IPv6 address.

All packets sent by the UE to a synthesized IPv6 address will be routedto the NAT64 node associated with the prefix64 of the IPv6 address. Whenthe NAT64 node receives the first IPv6 packet destined to the IPv4service it will create a translation state for this service. Thetranslation state includes inner and outer 5-tuples, in which each5-tuple holds the used upper layer protocol, protocol ports (or otherinfo) and the destination and source addresses. The inner 5-tuple willhold IPv6 addresses used by the UE (source=UE address,destination=synthesized IPv6 address). The outer 5-tuple will have IPv4addresses (source=IPv4 address from global address pool of NAT64,destination=IPv4 address from the host part of the synthesized IPv6address). After a NAT64 translation state has been created it can beused to translate the incoming and outgoing packets.

3GPP mobile core networks have a Policy and Charging Control (PCC)architecture for providing a fair allocation of resources to all UEsattached to the communications network and to gather charginginformation about the resources used. The PCC architecture holdssubscriber information of all the UEs in a Subscriber Policy Repository(SPR) node. The PCC architecture also includes a Policy and ChargingResource Function (PCRF), which is responsible for configuring UEspecific quality of service (QoS) settings to an IP-Connectivity AccessNetwork (IP-CAN) bearer session used for carrying the UE traffic. WhenUEs create new IP-CAN bearer sessions the PCRF node will acquire thesubscription information from the SPR node via a Sp reference point andset policies matching the subscription information to use in a packetdata network gateway (PDN GVV) via a Gx reference point. The PDN GW aPolicy and Charging Enforcement Function (PCEF) node is responsible forcontrolling the QoS settings for the IP-CAN bearer session dedicated tothe UE.

In a NAT64 node, the size of the translation state table or list for allUEs dictates the efficiency of the NAT64 node. This is because Internetservices can many connections to download small pieces of data (e.g.Google® maps where each map tile is uses its own connection). When NAT64node functionality is used in the 3GPP networks there is currently nocontrol over how many translation states can be created in a NAT64 nodefor each UE. This means that some UEs might get access to moretranslation states states, and hence services, than others. However, ifa static maximum limit were used per UE, then some services may berendered unusable once this limit is reached. At the same time, some UEsmight never require as many states as the maximum level would allow themto use, while others may use too many states overloading the NAT64 nodeor reducing the performance of other UEs.

A simple solution might be to deploy more NAT64 nodes, but this maystill result in an unfair distribution of translation load amongst theNAT64 nodes. In a network with multiple NAT64 nodes, it is desirablethat the translation load of the NAT64 nodes is evenly distributed.There is a need to dynamically monitor and control the NAT64 and DNS64communication resource usage amongst UEs to provide a fair usage ofcommunication resources.

SUMMARY

It is an object of the present invention to provide a mechanism forproviding a fair usage and amount of resources to all UEs in acommunications network.

According to a first aspect of the invention there is provided a methodfor operating a subscription control node in a communications network,the communications network including multiple UEs and multiple NAT64nodes, the subscription control node including subscription informationfor one or more of the UEs, the subscription information for each UEincluding translation state usage information associated with one ormore of the NAT64 nodes servicing the UE. The method includes collectingtranslation state usage information from each NAT64 node and identifyinga set of one or more UE(s) exceeding a maximum translation state usageallocated to each of the multiple UEs based on the correspondingsubscription information and the collected translation state usageinformation. In addition, the method includes adjusting the translationstate usage information in the subscription information of theidentified set of UE(s) to meet the maximum translation state usage foreach UE and updating the corresponding subscription information. Theupdated subscription information of the identified set of UE(s) istransmitted to the corresponding NAT64 nodes.

As an option, the step of collecting translation usage informationincludes receiving an update message from each NAT64 node, the updatemessage including an indication of the current number of translationstates each NAT64 node has allocated to each UE serviced by that NAT64node. Alternatively or additionally, the step of collecting translationusage information further includes calculating, for each UE, the totalnumber of translation states allocated to said each UE from thecollected translation state usage information.

Optionally, the step of identifying the set of UE(s) further comprisesincluding a UE in the set of UE(s) when the total number of translationstates for the UE exceeds the maximum number of translation statesallocated to that UE. The step of adjusting the translation state usageinformation in the subscription information of the identified set ofUE(s) may further include adjusting the maximum number of translationstates for each UE in the set of UE(s) that the corresponding NAT64nodes can allocate for said each UE. Additionally, the method mayinclude the step of receiving a request query from a first NAT64 node ofthe multiple NAT64 nodes for subscription information associated with afirst UE of the multiple UEs, and transmitting the subscriptioninformation associated with the first UE to the first NAT64 node, thesubscription information including the maximum number of translationstates that the first NAT64 node may allocate to the first UE.

As an option, the communication network may further include DNS64 node,and the method may further include the steps of receiving, from theDNS64 node, a request for a prefix address list associated with a secondUE of the multiple UEs for use in resolving a first type of IP addresswith a second type of IP address used in services requested by thesecond UE, retrieving, from the subscription information for one or moreof the UEs, data representative of the prefix address list associatedwith the second UE, and transmitting the data representative of theprefix address list associated with the second UE to the DNS64 node.

Optionally, the step of retrieving may include transmitting a requestquery to a subscription information storage node for subscriptioninformation associated with the second UE, receiving and storing thesubscription information associated with the second UE, and retrievingfrom the subscription information associated with the second UE the datarepresentative of the prefix address list associated with the second UE.

Alternatively, there is provided the steps of transmitting a requestquery to a subscription information storage node for subscriptioninformation associated with one or more of the multiple UEs, andreceiving and storing the subscription information associated with theone or more of the multiple UEs. Alternatively or additionally, themethod may further include the step of transmitting subscriptioninformation for one or more of the UEs to associated NAT64 nodes. Inaddition, there is provided the step of transmitting updatedsubscription information to the subscription information storage node,the updated subscription information including adjusted translationstate usage information for one or more UE(s).

According to a second aspect of the invention there is provided a methodfor operating a NAT64 node in a communications network including a UEand a subscription control node, where the NAT64 node includes a UE listof translation states for the UE, each translation state for use intranslating IP addresses from a first type of IP address to a secondtype of IP address for data packets received from the UE. The methodincludes the steps of receiving a data packet from the UE, the datapacket having a first type of IP address, translating the IP address ofthe data packet to a second type of IP address, when the IP address ofthe data packet corresponds to a translation state in the UE list. Themethod further includes determining if the current number of translationstates in the UE list is less than a maximum number of translationstates the NAT64 node can allocate to the UE when the IP address doesnot correspond to a translation state in the UE list. If the currentnumber of translation states is less than the maximum number oftranslation states allowable for the UE, then performing the steps ofcreating a new translation state corresponding to the IP address of thedata packet and updating the UE list when the current number oftranslation states is less than the maximum number of translationstates, updating the current number of translation states to include thenew translation state, and transmitting an update message to thesubscription control node including an indication of the current numberof translation states for the UE for use in tracking the total number oftranslation states in use for the UE.

As an option, the step of determining may further include sending aquery to the subscription control node for the maximum translationstates the NAT64 node can allocate to the UE. In addition, the methodmay include receiving a message including subscription information ofthe UE, the subscription information including the maximum number ofstates that the NAT64 node can allocate to the UE, and storing thesubscription information of the UE. As another option, the step ofdetermining further includes retrieving the maximum number of statesthat the NAT64 node can allocate to the UE from the stored subscriptioninformation of the UE. The method may further include removing atranslation state from the UE list when the connection establishedbetween the UE and the IP address associated with the translation stateis terminated, and updating the current number of states in the UE list.

Optionally, there is provided the step of transmitting a message to thesubscription control node indicating the updated current number ofstates in the UE list. Alternatively or additionally, there is providedsending an error message associated with the IP address of the receiveddata packet to the UE when the maximum number of translation states thatthe NAT64 node can allocate to the UE has been reached in the UE list.As an option, the step of transmitting the update message may includetransmitting the update message after a predetermined number of newtranslation states have been allocated to the UE. Additionally oralternatively, the step of transmitting the update message includestransmitting the update message periodically. As another option, thereis provided the step of receiving a resource request message from thesubscription control node and transmitting, to the subscription controlnode, a message including the current number of number of translationstates.

As an option, the communications network includes a second NAT64 node,the second NAT64 node includes a second UE list of translation statesfor the UE, and the method may further include the steps of receiving amessage including subscription information of the UE, the subscriptioninformation including a new maximum number of translation states thatthe NAT64 can allocate to the UE, the new maximum number of translationstates having been derived from the current number of translation statesof the UE list and the current number of translation states of thesecond UE list, and updating the maximum number of translation states ofthe UE list with the new maximum number of translation states.

According to a third aspect of the invention there is provided asubscription control node for use in a communications network, thecommunications network including multiple UEs and multiple NAT64 nodes,the subscription control node including a receiver, a transmitter, amemory unit, and a processor, the processor being connected to thereceiver, to the transmitter, and to the memory unit. The memory unitincludes storage for subscription information for one or more of theUEs, the subscription information for each UE including translationstate usage information associated with one or more of the NAT64 nodesservicing the UE. The processor and transmitter are configured tocollect translation state usage information from each NAT64 node. Theprocessor is further configured to identify a set of one or more UE(s)exceeding a maximum translation state usage allocated to each of themultiple UEs based on the corresponding subscription information and thecollected translation state usage information. The processor is alsoconfigured to adjust the translation state usage information in thesubscription information of the identified set of UE(s) to meet themaximum translation state usage for each UE, and updating thecorresponding subscription information. The transmitter is furtherconfigured to transmit the updated subscription information of theidentified set of UE(s) to the corresponding NAT64 nodes.

As an option, the processor, receiver, and transmitter are furtherconfigured to receive a request query from a first NAT64 node of themultiple NAT64 nodes for subscription information associated with afirst UE, retrieve the subscription information associated with thefirst UE, and transmit the subscription information associated with thefirst UE to the first NAT64 node, the subscription information includingthe maximum number of translation states that the first NAT64 node mayallocate to the first UE. As another option, the communication networkfurther comprises a DNS64 node, and the processor, transmitter andreceiver are further configured to receive, from the DNS64 node, arequest for a prefix address list associated with a second UE of themultiple UEs for use in resolving a first type of IP addresses with asecond type of IP addresses for the second UE, to retrieve, from thesubscription information for one or more of the UEs, data representativeof the prefix address list associated with the second UE, and transmitthe data representative of the prefix address list associated with thesecond UE to the DNS64 node.

According to a fourth aspect of the invention there is provided a NAT64node in a communications network, the communication network including aUE and a subscription control node, the NAT64 node including a receiver,a transmitter, a memory unit, and processor, the processor beingconnected to the receiver, to the transmitter, and to the memory unit.The memory unit includes storage for a UE list of translation states forthe UE, each translation state for use in translating IP addresses froma first type of IP address to a second type of IP address for datapackets received from the UE. The receiver is configured for receiving adata packet from the UE, the data packet having a first type of IPaddress, the processor is configured for translating the IP address ofthe data packet to a second type of IP address, when the IP address ofthe data packet corresponds to a translation state in the UE list. Theprocessor is further configured to determine if the current number oftranslation states in the UE list is less than a maximum number oftranslation states the NAT64 node can allocate to the UE when the IPaddress does not correspond to a translation state in the UE list. Ifthe current number of translation states is less than the maximum numberof translation states allowable for the UE, then the processor andtransmitter are further configured to create a new translation statecorresponding to the IP address of the data packet and update the UElist when the current number of translation states is less than themaximum number of translation states, update the current number oftranslation states to include the new translation state, and transmit anupdate message to the subscription control node including an indicationof the current number of translation states for the UE for use intracking the total number of translation states in use for the UE.

As an option, the communications network includes a second NAT64 node,the second NAT64 node includes a second UE list of translation statesfor the UE, the processor and receiver are further configured to receivea message including subscription information of the UE, the subscriptioninformation including a new maximum number of translation states thatthe NAT64 node can allocate to the UE, the new maximum number oftranslation states having been derived from the current number oftranslation states of the UE list and the current number of translationstates of the second UE list, and update the maximum number oftranslation states of the UE list with the new maximum number oftranslation states.

As an option, the subscription information storage node is an SPR nodeand the subscription control node is a PCRF node. In addition, the firsttype of IP address is an IPv6 address and the second type of IP addressis an IPv4 address.

Embodiments of the present invention can provide a relatively simple andefficient mechanism for providing a fair usage and amount of resourcesto all UEs in a communications network. This provides a way foroperators to provide differentiated services for UEs and dynamicallycontrol the resource consumption inside core networks and insidedifferent NAT64 nodes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates schematically a communication network according toembodiments of the present invention;

FIG. 2a illustrates schematically a signal flow diagram of an examplesolution according to the present invention;

FIG. 2b illustrates schematically a signal flow diagram of anotherexample solution according to the present invention;

FIG. 3a illustrates schematically a flow diagram of an example processfor use by a subscription control node according to embodiments of thepresent invention;

FIG. 3b illustrates schematically another flow diagram of an exampleprocess for use by a subscription control node according to embodimentsof the present invention.

FIG. 3c illustrates schematically a further flow diagram of an exampleprocess for use by a subscription control node according to embodimentsof the present invention.

FIG. 3d illustrates schematically yet another flow diagram of an exampleprocess for use by a subscription control node according to embodimentsof the present invention.

FIG. 4a illustrates schematically a flow diagram of an example processfor use by a NAT64 node according to embodiments of the presentinvention;

FIG. 4b illustrates schematically another flow diagram of an exampleprocess for use by a NAT64 node according to embodiments of the presentinvention;

FIG. 4c illustrates schematically a further flow diagram of an exampleprocess for use by a NAT64 node according to embodiments of the presentinvention;

FIG. 4d illustrates schematically yet another flow diagram of an exampleprocess for use by a NAT64 node according to embodiments of the presentinvention;

FIG. 5 illustrates schematically a subscription control node accordingto embodiments of the present invention; and

FIG. 6 illustrates schematically a NAT64 node according to embodimentsof the present invention.

DETAILED DESCRIPTION

In order to at least partially overcome the problems described above, itis proposed herein to improve the mechanism for providing fair usage ofresources by controlling and monitoring the amount of resources UEsreceive in a communication network. In particular, mechanism usessubscription information and the NAT64 and DNS64 functions by includinga new reference point between the policy control and charging (PCC)architecture and the NAT64 and DNS64 nodes. This reference point can beused to download specific information for each UE from the subscriptionpolicy repository to the NAT64 and DNS64 nodes, when the specificinformation is needed. The reference point may be used to relay charginginformation to the PCC from a NAT64 node. In addition, further usefulinformation related to the UE subscription is now available to the PCCand SPR and can be stored.

In particular, the mechanism may provide the NAT64 node with UE specificinformation on the number of translation states each UE is allowed touse at the same time and at any given time. This information needs to beupdated because the UE traffic may be divided between more than oneNAT64 node at the same time. Initially, each NAT64 node servicing a UEmay request this information via the new reference point from the PCCarchitecture, for example from the PCRF node, when the first translationstate for the UE is created. The PCRF node may communicate the maximumnumber of translation states that the NAT64 node may be allowed toallocate to the UE. After this the NAT64 keeps count of the number oftranslation states it has allocated to the UE, and to create translationstates for the UE until a given limit of translation states for thatNAT64 node has been reached. Upon determining when a UE has beenallocated translation states by one or more NAT64 nodes, the PCRF nodemay include further logic to control the total number of UE translationstates that can be allocated by all the NAT64 nodes. The PCRF node canactively monitor the number of translation states by requesting atranslation state count per UE from each NAT64 node, and in response, itcan lower and increase the translation state limits for each UE servicedby each of the NAT64 nodes based on the used amount of translationstates for the UE, the network load, and the UE subscriptioninformation. In addition, each NAT64 node may be arranged to keep a logor list of translation states allocated per UE, and reports theseamounts to the PCRF node for monitoring and charging purposes.

In addition to monitoring and controlling each NAT64 node in allocatingtranslation states to each UE, the mechanism may further provide theDNS64 node with specific UE information and/or NAT64 node resourceconsumption information when the DNS64 node synthesizes an IPv6address(es) upon a Uniform Resource Location (URL) resolve request fromone or more UE(s). The DNS64 node can use the new reference point todownload UE subscription information from the PCC architecture, e.g. thePCRF node, when it receives a DNS request from a UE for the first time.The DNS64 node can then cache the UE subscription information for thesubsequent DNS requests. The UE subscription information may include apriority list of the allowed NAT64 nodes for the given UE. During peakhours the PCRF node may further relay priority levels of NAT64 nodes tothe DNS64 node in order for the DNS64 node to select a pref64 for aNAT64 node that has the lowest level of resources consumed (e.g. thelowest levels of used translation states for a given UE, a set of UEs,or from all UEs). The PCC architecture may further relay information tothe DNS64 node when some NAT64 nodes should not accept more connectionsfrom a given UE, a set of UEs, or from all UEs.

FIG. 1 illustrates a schematic diagram of a communication network 100for an example NAT64 and DNS64 node deployment for use in the examplesolutions of monitoring and controlling communication resources usage byUEs 102 a-102 n. The communication network 100 further includes a radioaccess network (RAN) 106 providing UEs 102 a-102 n with access to a corenetwork 107 (e.g. a 3GPP core network based on 3GPP TR 23.975), a PDN GW110, and IPv4/IPv6 operator PDN, NAT64 nodes 103 a-103 m, DNS64 nodes104 a-104 l, and IPv4 and IPv6 Internet 108 including IPv4 and IPv6networks.

Communication network 100 further includes PCC architecture such as PCRFnode 101 that is in communication with one or more of the NAT64 nodes103 a-103 m some of which are deployed or co-located in PDN GW 110 andsome of which may be deployed or co-located with one or more DNS64 nodes104 a-104 l in IPv6 service domain 112. Enabling communication betweenthe PCC architecture such as PCRF node 101 and NAT64 nodes 103 a-103 mand DNS64 nodes 104 a-104 l is a reference point labelled the “New Gx”reference point.

In communication network 100, some UEs 102 a-102 n may communicate usingIPv6 addressing, so for traffic directed to/from IPv6 networks there isno need for IP address conversion. In this case, the UEs 102 a-102 n maydirectly access the IPv6 networks in the IPv4 and IPv6 Internet 108 viaRAN 106, core network 107, PDN GW 110, and IPv4/IPv6 operator PDN. Fortraffic directed to/from IPv4 networks, UEs 102 a-102 n may communicatewith the IPv4 networks in the IPv4 and IPv6 Internet 108 using IPv6addressing via RAN 106, PDN-GW 110, DNS64 nodes 104 a-104 l and/or NAT64nodes 103 a-103 m, and IPv4/IPv6 operator PDN.

The communications network 100 includes a subscription policy repository105 that includes subscription information related to the UEs 102 a-102n. This UE subscription information may include the subscriptioninformation as specified in 3GPP TS 23.203 (e.g. section 6.2.4). Incommunications network 100, the SPR node 105 is in communication withPCRF node 101 and so has access to further UE specific subscriptioninformation, which may be included with the UE subscription information.

UE specific subscription information may comprise or represent any UEsubscription information such as subscriber information related to NAT64and/or DNS64 nodes 103 a-103 m or 104 a-104 l for one or more UEs 102a-102 n. Examples of UE specific subscription information that may beused in certain examples or embodiments of the described communicationnetwork 100 is UE information related to the allowed UE service type forthe NAT64 and DNS64 services, maximum number of translation statesallowed for the UE for each NAT64 node, priority list of the allowedNAT64 nodes for the UE, NAT64 charging policy information of the UE.

The PCRF node 101 is in communication with the SPR node 105 via an Spreference point and in communication with the NAT64 nodes 103 a-103 mand the DNS64 nodes 104 a-104 l by the “new Gx” reference point. Thismeans the UE subscription information stored at SPR node 105 may becommunicated with PCRF node 101 and NAT64 nodes 103 a-103 m and DNS64nodes 104 a-104 l. In addition, the UE subscription information mayfurther include UE specific subscription information related to theNAT64 nodes 103 a-103 m and DNS nodes 104 a-104 l. PCRF node 101 can beconfigured to query SPR node 105 for UE subscription informationincluding UE specific subscription information for use in controllingand updating the NAT64 nodes 103 a-103 m and/or DNS64 nodes 104 a-104 l.The PCRF node 101 may further update the UE specific subscriptioninformation and further update the SPR node 105 with UE specificinformation updates generated by NAT64 nodes 103 a-103 m and/or DNS64nodes 104 a-104 l or even the PCRF node 101.

The SPR node 105 notifies the PCRF node 101 when the UE subscriptioninformation (and UE specific subscription information) changes forparticular UEs. This may be due to the operator updating thesubscription information of a UE due to changes to a service plan for auser of a UE. In addition, the NAT64 charging information can begathered from the NAT64 nodes 103 a-103 m following the chargingpolicies in SPR node 105 and then sent to the Online Charging System(OCS) by the PCRF node 101 in a format specified for the Sy referencepoint.

In the PCC architecture, the PCRF node 101 uses a Gx reference point tocommunicate with a PCEF node (not shown) and via the Gx reference pointthe PCRF node 101 has dynamic control over the PCC functionality in thePCEF node. The Gx reference point enables PCEF node to request policydecisions from PCRF node 101, and enables the PCRF node 101 to deliverIP-CAN specific parameters and policy decisions to PCEF node, etc. The“New Gx” reference point between the NAT64 nodes 103 a-103 m and DNS64nodes 104 a-104 l to the PCRF node 101 allows the PCRF node 101 tomonitor and control the NAT64 and DNS64 communication resources used byUEs.

The “New Gx” reference point may be implemented by extending or using asubset of the existing Gx reference point architecture. The existing Gxreference point is located between the PCRF node and the PCEF nodes andcan be used for charging control, policy control or both, which includessharing UE subscription information. In addition to some of thefunctionality of the existing Gx reference point, the “New Gx” referencepoint may comprise or represent a reference point that allows the NAT64nodes 103 a-103 m, DNS64 nodes 104 a-104 l, and PCRF node 101 tocommunicate with each other for use in monitoring and controlling theNAT64 and DNS64 communication resource usage of UEs. Examples ofcommunication over the “New Gx” reference point that may be used incertain examples or embodiments of the described communications networksmay further allow a) NAT64 nodes 103 a-103 m to request UE maximumtranslation state value from PCRF node 101; b) the PCRF node 101 toupdate the maximum state values for UEs in corresponding NAT64 nodes 103a-103 m; c) the NAT64 nodes 103 a-103 m to inform PCRF node 101 aboutresource usage of UEs serviced by the NAT64 nodes 103 a-103 m; d) theDNS64 nodes 104 a-104 l to request pref64s allowed for a UE, and e) thePCRF node 101 to update priority order of UE pref64s in DNS64 nodes 104a-104 l.

An example solution is now described for the mechanism for providing afair usage and amount of resources to all UEs 102 a-102 n incommunications network. 100. In particular, the mechanism allowing thePCC architecture, e.g. the PCRF node 101, to interact with one or moreNAT64 nodes 103 a-103 m and one or more DNS64 nodes 104 a-104 l that maybe servicing the UEs 102 a-102 n. This provides a way for operators toprovide differentiated services for UEs and dynamically control theresource consumption inside core networks and inside different NAT64 andDNS64 nodes 103 a-103 m and 104 a-104 l.

FIGS. 2a and 2b illustrate signalling flow diagrams of example solutionsfor providing fair usage of communication resources for UEs 102 a-102 nin communications network 100, In particular, FIG. 2a illustrates asignalling flow diagram of a process 200 for an example solution foroperating a subscription control node (e.g. a PCRF node 101), asubscription storage node (e.g. a SPR 105 node) and a NAT64 node 103 a,FIG. 2b illustrates a signalling flow diagram of an example solution foroperating a subscription control node (e.g. PCRF 101), a subscriptionstorage node (e.g. SPR 105) and a DNS64 node 104 a. In the followingdescription, the references used in FIG. 1 will be reused for like orsimilar network components.

Referring to FIG. 2a , the process 200 illustrates the PCC architectureand NAT64 interaction for providing fair usage of NAT64 communicationresources of a NAT64 node 103 a servicing a UE 102 a. As illustratedthere are several processes showing the PCC architecture (PCRF node 101and SPR 105) interacting with a NAT64 node 103 a. These processesinclude: 1) “Initial IPv6 Traffic” scenario 201 where a UE 103 a isusing services of a NAT64 node 103 a for the first time, 2) “Update UESubscription Information” scenario 202, which allows dynamic update ofmaximum translation state amounts and limits, and 3) “ChargingInformation Update” process 203 for letting the NAT64 node 103 a knowhow much UE traffic it has been handling.

It is assumed that UE 102 a has already communicated with a DNS64 node(not shown) and has an IPv6 address synthesized by the DNS64 node. Instep 1 of the “Initial IPv6 Traffic” process 201, UE 102 a initiates aNAT64 translation by sending a first IPv6 packet to the IPv6 addresssynthesized by the DNS64 node. It is assumed that the UE. The first IPv6packet may be, for example, the first TCP SYN segment. When receivingthis message the NAT64 node 103 a determines from its internalcache/database whether it already has the NAT64 UE specific subscriptioninformation for UE 103 a related to the maximum translation state value(MTSV) or limit for the UE 103 a. The NAT4 node 103 a may identify UE102 a by the IPv6 source address in the received IPv6 packet header. Ifthe MTSV for UE 102 a is known to NAT64 node 103 a and UE 102 a has notexceeded the MTSV or the maximum allowed number of translation statesthat the NAT64 node 103 a may use, then the NAT64 node 103 a may createor add a new translation state to the list of translation states for UE102 a and begin translating the traffic related for this state.Otherwise the process 201 proceeds to step 2.

In step 2, if the NAT64 node 103 a doesn't have the NAT64 UE specificsubscription information, then it sends a message to the PCRF node 101requesting the related UE specific subscription information for UE 102a. In this example, the NAT64 node 103 a uses the “New Gx” referencepoint interface between NAT64 node 103 a and PCRF node 101. The requestmessage will include the IPv6 source address of UE 103 a so that PCRFnode 101 may identify UE 103 a.

On receiving the request message from the NAT64 node 103 a in relationto UE 102 a, the PCRF node 101 locates the UE identifier using thereceived IPv6 address of UE 102 a and uses this UE identifier to searchfor the NAT64 UE specific subscription information for UE 102 a. If theUE specific subscription information for UE 102 a is located locally,then the process 201 proceeds to step 5 where the PCRF node 101 sendsthe UE specific subscription information for UE 103 a back to the NAT64node 103 a. However, if the UE specific subscription information for UE103 a is not located with the PCRF node 101, then the PCRF node 101requests this information from SPR node 105 in step 3.

In step 3, the PCRF node 101 sends a request message to SPR node 105,which may be via the updated Sp reference point. The request messageincludes data representative of the UE identifier for UE 102 a that isused to identify UEs within the PCC architecture. On receiving therequest message from the PCRF node 101, the SPR node 105 locates theNAT64 UE specific subscription information (e.g. the maximum number ofallowed translation states for UE 102 a, NAT64 service charging policiesfor UE 102 a, etc.) for the UE 102 a from a database or storageaccessible to the SPR 105. In step 4, the requested NAT64 UE specificsubscription information is sent back to the PCRF node 101 through the“New Gx” reference point. On receiving the NAT64 UE specificsubscription information for UE 103 a from SPR node 105, the PCRF node101 will update its local database or storage and stores the NAT64policy information of the UE 102 a locally.

In step 5, the PCRF node 101 provisions the NAT64 node 103 a with the UEspecific subscription information of UE 102 a via the “New Gx” referencepoint. Once the NAT64 node 103 a has the UE specific subscriptioninformation of UE 102 a, then the NAT64 node 103 a can handle subsequenttranslation state creations and rejections in relation to UE 102 a basedon the received UE specific subscription information. In addition, theNAT64 node 103 a can follow the charging policy rules set by the PCCarchitecture.

To dynamically update the NAT64 UE specific subscription information forUEs that are being serviced by the NAT64 node 103 a the PCC can use the“Update UE Subscription Information” messaging process 202 illustratedin FIG. 2a . In step 1 a resource consumption information exchangebetween the NAT64 nodes 103 a-103 m and the PCC architecture, in thisexample the PCRF node 101, is performed. The NAT 64 nodes 103 a-103 mare configured to report resource usage of UEs 102 a-102 n beingserviced by the NAT64 nodes 103 a-103 m to the PCRF node 101. Thisallows the PCRF node 101 to analyse the resource usage and control theNAT64 services provided to UEs 102 a-102 n in a fair manner and whichalso follows the subscribed services for the UEs 102 a-102 n. Thisresource consumption information exchange is performed by the NAT64nodes 103 a-103 m reporting their resource usage or consumptionperiodically, and/or by having the PCRF node 101 request the resourceconsumption information (also known as resource usage information),which may occur when management cycles are run in the PCRF node 101. Itis to be appreciated that a combination of these reporting methods maybe used.

Once the PCRF node 101 has the resource consumption information fromeach NAT64 node 103 a-103 m it can use internal logic/algorithms todetermine if some UEs 102 a-102 n are found to be using too much NAT64resources. That is, a set of one or more UEs 102 a-102 n are found bythe PCRF node 101 to be using more translation states than have beenallocated to them by their subscription, or using more translationstates than have been allocated to the corresponding NAT64 node 103a-103 m by the PCRF node 101. As multiple NAT64 nodes 103 a-103 m canserve a UE 103 a, the PCRF node 101 can limit the number of translationstates each NAT64 node 103 a-103 m can allocate to the UE 102 a forbalancing the NAT64 resource usage in the communication network 100.

In performing the analysis and control, the PCRF node 101 can initiate aUE specific subscription information update when a set of UEs from UEs102 a-102 n in communication network 100 are using excessive NAT64resources. If necessary, for example, the PCRF node 101 can issuecontrol messages to “demand” a particular NAT64 node 103 a should notaccept anymore UE translation states in relation to one or more UEs 102a-102 n, or issue control messages to indicate that some other NAT64nodes 103 b-103 m should allow the subsequent UE translation states inrelation to the one or more UEs 102 a-102 n.

In step 2 of the “Update UE Subscription Information” messaging process202, with reference to UE 102 a and NAT64 node 103 a, if the UE specificsubscription information for UE 102 a is updated inside the SPR node 105then the updated UE subscription information is notified to the PCRFnode 101 so that the update can take effect for the services provided toUE 102 a. The SPR node 105 sends an update message to the PCRF node 101,the update message including UE subscriber information, which mayinclude UE specific subscriber information in relation to UE 103 a. Onreceiving the updated UE subscriber information for UE 102 a, the PCRFnode 101 updates its UE subscriber information for UE 102 a and thencalculates based on the internal logic the new resource usage orconsumption information that may be needed for use in each NAT64 node103 a-103 m. The new resource usage or consumption information mayinclude a new limit for the maximum number of translation states, andfor each NAT64 node 103 a-103 m serving UE 102 a it may also include themaximum number of translation states that a NAT64 node 103 a may use inrelation to UE 102 a. This information is included into the UE specificsubscription information for UE 103 a and sent to the correspondingNAT64 nodes 103 a-103 m that serve UE 102 a.

The PCRF node 101 then sends, in step 3, update message(s) in relationto the UE specific subscription information for UE 102 a to the NAT64nodes 103 a-103 m serving UE 102 a. The PCRF node 101 can send theupdated subscription information to the NAT64 nodes 103 a-103 m servingUE 102 a through the “New Gx” reference point. The PCRF node 101 usesthe IPv6 address of UE 102 a to specify to the NAT64 nodes 103 a-103 mthe UE specific subscription information that is needed to be updated.

In step 4, after an update as described in step 3, subsequent IPv6packets sent by UE 102 a to an updated NAT64 node, e.g. NAT64 node 103a, that would result in the creation of a new translation state for UE102 a are handled based on the updated UE specific subscriptioninformation the NAT64 node 103 a received from PCRF node 101. In step 5,if the NAT64 node 103 a determines that UE 102 a has exceeded themaximum number of states allowed or the maximum number of states thatNAT64 node 103 a is allowed to create for UE 102 a, then the statecreation will be rejected and an ICMPv6 error message indicating thiscan be sent from the NAT64 node 103 a to the UE 102 a.

It is to be appreciated that the messaging over the “New Gx” referencepoint is also used for sending charging information for UEs 102 a-102 nfrom the NAT64 nodes 103 a-103 m serving the UEs to the PCC architectureif required by the operator. In particular, “Charging InformationUpdate” process 203 can be performed by the NAT64 nodes 103 a-103 m. Inthis example, NAT64 node 103 a is configured to periodically send datarepresentative of charging information based on the UE subscriptioncharging policies set by the operator. This information may be sent overthe “New Gx” reference point to the PCRF node 101, where the PCRF node101 forwards to the OCS function inside the PCC architecture by using aSy reference point. Alternatively or additionally, the NAT64 node 103 acan be further configured to receive charging information requestmessages from PCRF node 101. The PCRF node 101 may send requests forcharging information to NAT64 nodes 103 a-103 m in relation to aparticular UE, e.g. UE 102 a, or to set or lists of UEs 102 a-102 nbased on the operator's preferences.

FIG. 2b illustrates a signalling flow diagram of an example solution foroperating a subscription control node (e.g. PCRF 101), a subscriptionstorage node (e.g. SPR 105) and a DNS64 node 104. FIG. 2b illustrates aDNS64 and PCC interaction process 210 for providing fair usage ofcommunication resources in relation to UE 102 a. In particular, process210 may include a “Initial DNS Resolve” process 211 and a “Update UESubscription Information” process 212. The “Initial DNS Resolve” process211 relates to when the DNS64 node 104 receives a DNS query from a UE102 a in which DNS64 node 104 has not yet cached the information for UE102 a. The “Update UE Subscription Information” process 212 relates towhen the UE subscription information for UE 102 a is updated in the SPRnode 105, such that the DNS64 node 104 should be updated. The updated UEsubscription information, which may include specific UE subscriptioninformation, is sent to the DNS64 node 104 via the PCRF node 101.

Referring to “Initial DNS Resolve” process 211, in step 1, UE 102 asends a AAAA (so-called quad-A) DNS request for a service. The DNS64node 104 searches for the pref64 list of UE 102 a in its internal policydatabase/cache. If the entry for the pref64 list of UE 102 a is found,then the DNS64 node 104 proceeds to step 6 where it synthesizes the IPv6address for the service and replies to the DNS request. Otherwise, theprocess 211 proceeds to step 2, when it is determined whether the UEsubscription information is available to the DNS64 node 104. In step 2,if the UE subscription information is not present in the DNS64 node 104,the DNS64 node 104 transmits to the PCRF node 101 a “UE SubscriptionInformation” request message for the UE subscription information, whichmay include the UE specific subscription information. This may be sentvia the “New Gx” reference point. The DNS64 node 104 includes in the “UESubscription Information” request message the source IPv6 address of UE102 a as a key to allow the PCRF node 101 to identify UE 102 a.

When the PCRF node 101 receives the “UE Subscription Information”request message from the DNS64 node 104, it will use the IPv6 address ofthe UE 102 a to search through its locally stored UE subscriberinformation to locate the UE identifier used internally in the PCCarchitecture for locating UE subscription information. The PCRF node 101may or may not have locally stored the DNS64 specific information forthe UE when creating the IP-CAN bearer. However, if the DNS64 specificinformation is available to the PCRF node 101, then the PCRF node 101performs step 5 in which the DNS64 specific information including thepriority list of pref64s for UE 102 a is sent to the DNS64 node 104. Ifthe PCRF node 101 does not have the required DNS64 information such asthe pref64 information of UE 102 a, then in step 3, the PCRF node 101sends a “UE Subscription Information” request message requesting thisinformation from the SPR node 105, the “UE Subscription Information”request message includes the UE identifier for UE 102 a. In sending the“UE Subscription Information” request message for DNS64 UE specificsubscription information of UE 102 a, the PCRF node 101 may use theupdated Sp reference point.

On receiving the “UE Subscription Information” request message for theDNS64 UE specific information for UE 102 a from the PCRF node 101, theSPR node 105 locates the required information, e.g. the priority list ofpref64 for UE 102 a, and in step 4, the SPR node 105 transmits a “UESubscription Information” response message to the PCRF node 101, the “UESubscription Information” response message includes the priority list ofpref64 for the UE 102 a identified by the UE identifier. On receivingthe “UE Subscription Information” response message from SPR node 105,the PCRF node 101 updates its local storage/database to include thepriority list of pref64 for UE 102 a. In step 5, the PCRF node sends a“UE Subscription Information” response to the DNS64 node with the DNS64UE specific information including the priority list of pref64s for UE102 a. This may be performed using the “New Gx” reference point.

On receiving the DNS64 UE specific information, the DNS64 node 104 canresolve the IPv4 and IPv6 addresses for the services UE 102 a requestedbefore or after acquiring the pref64 information for the UE 102 a. TheDNS64 node 104 caches the requested DNS64 UE specific information of UE102 a from PCRF node 101, then if necessary, the DNS64 node 104 uses thehighest priority pref64 to synthesize an IPv6 destination address forthe service requested by UE 102 a. In step 6, this IPv6 address is thenreturned to the UE 102 a in a DNS Reply message including thesynthesized IPv6 Address.

When UE information is updated in the SPR node 105 or the resourcesituation in the NAT64 nodes 103 a-103 m changes, the PCRF node 101performs the “Update UE Subscription Information” process 212. Theinitial update event to update the priority list of pref64 may come fromthe SPR node 105 when the UE subscription information for a UE, such asUE 102 a, is changed or when the PCRF node 101 determines that one ormore NAT64 nodes 103 a-103 m are fully used. That is based on networkloading of the NAT64 nodes 103 a-103 m.

In step 1, it has been assumed that the UE subscription information forUE 102 a at the SPR node 105 has been updated, therefore, the updateevent is initiated through the Sp reference point by the SPR node 105 bysending a Notification message with the updated pref64 list to the PCRFnode 101. The Notification message includes the updated UE subscriptioninformation for UE 102 a. It is to be appreciated that the PCRF node 101can also initiate the update procedure based on internallogic/algorithms. On receiving the Notification message including theupdated pref64 list for UE 102 a, in step 2, the PCRF node 101 sends theupdated priority ordered list of pref64s to the DNS64 node 104 in the“UE Subscription Information” message, which includes the priority listof pref64:s. The “New Gx” reference point may be used. On receiving theDNS64 will update the locally stored pref64 list for UE 102 a so thesubsequent DNS request from the “UE Subscription Information” message,the UE 102 a will be handled based on the updated priority list.

In step 3, the UE 102 a may resolve a new URL by sending the DNS64 node104 a SNR Query message including the URL of the requested service, instep 4, the DNS64 node 104 selects the pref64 for the synthesizedaddress from the updated pref64 list of UE 102 a.

It is to be appreciated that although the DNS64 UE specific subscriptioninformation includes a priority list of pref64s for a UE, the messagingdescribed in the above update may further include policies for pref64usage for specific services. In this way, the DNS64 nodes can becontrolled to synthesize IPv6 addresses for handling communication withthe appropriate NAT64 node. For example, an operator may have a policyof dedicating a first NAT64 node for video streaming services and asecond NAT64 node for website traffic. The DNS64 nodes may be updatedbased on processes 211 and 212 to include this policy information inrelation to the pref64 usage. The DNS64 nodes can then be configured tosynthesize IPv6 addresses directed to the first NAT64 node for videostreaming services and synthesize IPb6 addresses directed to the secondNAT64 node.

FIG. 3a illustrates schematically a flow diagram of another examplesolution for operating a policy or subscription control node (e.g. aPCRF node 101) in communication network (e.g. communications network100). It is assumed that the communications network includes multipleUEs and multiple NAT64 nodes. The subscription control node alsoincludes subscription information for one or more of the UEs, in whichthe subscription information for each UE includes translation stateusage information associated with one or more of the NAT64 nodesservicing the UE. The steps performed by the subscription control nodeinclude:

-   A1. Collecting translation state usage information from NAT64 nodes    in the communication network. This may include receiving periodic    translation usage information from each NAT64 node, or a set of    NAT64 nodes in the communication network, or this may include    sending requests for translation state usage information from some    of the NAT64 nodes in the communication network and receiving    responses from the corresponding NAT64 nodes. The translation state    usage information from the NAT64 nodes is processed and stored by    the subscription control node. The translation usage information for    a NAT64 node may include the current number of translation states    allocated to a UE or to each UE that is being served by the NAT64    node or the maximum number of translation states for each UE served    by the NAT64 node. Other translation state usage information may    include the number of unallocated translation states for each UE or    the total number of unallocated translation stated in the NAT64    node.-   A2. The subscription control node may process the collected    translation usage information to identify a set of one or more UE(s)    exceeding a maximum translation state usage allocated to each of the    multiple UEs based on the corresponding subscription information and    the collected translation state usage information.-   A3. On identifying the set of one or more UEs exceeding the maximum    translation state usage, the subscription control node may adjust    the translation state usage information stored in the subscription    information for each UE of the identified set of UE(s) such that    each UE will meet their maximum translation state usage.-   A4. The subscription information for each UE stored by the    subscription control node is updated based on the adjusted    translation state information for each of the identified UEs.-   A5. The subscription control node transmits the updated subscription    information of the identified set of UE(s) to the corresponding    NAT64 nodes.

In addition, the updated subscription information associated with thefirst UE may be transmitted from the subscription control node to asubscription information storage node (e.g. SPR 105). The updatedsubscription information may include adjusted translation state usageinformation for one or more UE(s).

FIG. 3b illustrates schematically another flow diagram of an examplesolution for process for operating the subscription control node in thecommunication network. The same assumptions are considered as for theexample solution in FIG. 3a . The steps performed by the subscriptioncontrol node, for each UE of the multiple UEs, may include:

-   B1. Collecting translation usage information at the subscription    control node by receiving an update message from a first NAT64 node    of the multiple NAT64 nodes, the update message including an    indication of the current number of translation states that the    first NAT64 node has allocated to a first UE of the multiple UEs.-   B2. Calculating the total number of translation states allocated to    the first UE. This may include making queries to other NAT64 nodes    for translation state usage information associated with the first    UE, or receiving from other NAT64 nodes translation state usage    information associated with the first UE. Determining whether the    first UE exceeds a maximum number of translation states allocated to    the first UE and proceeding to step B3.-   B3. If the first UE exceeds a maximum number of translation states    allocated to the first UE, then adjusting the maximum number of    translation states that the first NAT64 node can allocate to the    first UE, proceed to B4. Alternatively or additionally, this may    include adjusting the maximum number of translation states that    another NAT64 node can allocate to the first UE, proceed to B4. If    the first UE does not exceed the maximum number of translation    stated then proceed to B1 to collect further translation state usage    information in relation to the first UE from the first or other    NAT64 nodes.

Alternatively or additionally, step B3 may include identifying a set ofUEs including the first UE should it be determined that the UEs in theset of UEs exceed the maximum number of translation states that eachNAT64 node may allocate, then further adjusting the maximum number oftranslation states for each UE in the set of UE(s) that thecorresponding NAT64 nodes can allocate for said each UE.

-   B4. Updating the subscription information associated with the first    UE based on the adjusted maximum number of translation states.-   B5. Transmitting the updated subscription information associated    with the first UE to the first NAT64 node. Alternatively or    additionally, transmitting the updated subscription information to    other NAT64 nodes serving the first UE.

In addition, the updated subscription information associated with thefirst UE may be transmitted from the subscription control node to asubscription information storage node (e.g. SPR 105). The updatedsubscription information may include adjusted translation state usageinformation for one or more UE(s).

FIG. 3c illustrates schematically a further flow diagram of an examplesolution for use by the subscription control node (e.g. PCRF node 101)when interacting with a first NAT64 node. The subscription control nodemay perform a process based on the following steps:

-   C1. Receiving, at the subscription control node, a request query    from a first NAT64 node of the multiple NAT64 nodes for subscription    information associated with a first UE of the multiple UEs. The    subscription information may include NAT64 UE specific subscription    information associated with the first UE. This may include the    maximum number of translation states associated with the first UE,    or the maximum number of translation states that the first NAT64    node may allocate to the first UE.-   C2. Determining whether the subscription information associated with    the first UE is stored or found at the subscription control node. If    the subscription information is located at the subscription control    node then the process proceeds to step C5. If the subscription    information is not stored or found at the subscription control node    then the process proceeds to step C3.-   C3. Transmitting, from the subscription control node, a request    query to a subscription storage node (e.g. an SPR node 105) for    subscription information associated with the first UE. The request    query may include data representative of a UE identifier and the    requested subscription information. The requested subscription    information may be NAT64 UE specific subscription information.-   C4. Receiving, at the subscription control node, a notification    message from the subscription storage node, the notification message    including the requested subscription information associated with the    first UE. This requested information may be stored or used to update    the subscription information associated with the first UE at the    subscription control node.-   C5. Transmitting from the subscription control node the requested    subscription information to the first NAT64 node, the subscription    information including the maximum number of translation states that    the first NAT64 node may allocate to the first UE.

FIG. 3d illustrates schematically yet another flow diagram of an examplesolution of a process for use by the subscription control node (e.g.PCRF node 101) when interacting with a first DNS64 node. Thesubscription control node may perform a process based on the followingsteps:

-   D1. Receiving, at the subscription control node, a request query    from a first DNS64 node, the request query including a request for    DNS64 UE subscription information associated with a first UE of the    multiple UEs for use in resolving a first type of IP address with a    second type of IP address used in services requested by the first    UE. The DNS64 UE subscription information including DNS64 UE    specific subscription information such as a prefix address list    associated with the first UE.-   D2. Determining whether the DNS64 UE subscription information    associated with the first UE is stored or found at the subscription    control node. The subscription information including the prefix    address list associated with the first UE. If the requested    subscription information is located at the subscription control node    then the process proceeds to step D5. If the requested subscription    information is not stored or found at the subscription control node    then the process proceeds to step D3.-   D3. Transmitting, from the subscription control node, a request    query to a subscription storage node (e.g. an SPR node 105) for the    requested subscription information associated with the first UE. The    request query may include data representative of a UE identifier and    the requested subscription information. The requested subscription    information may be DNS64 UE specific subscription information    including a prefix address list associated with the UE.-   D4. Receiving, at the subscription control node, a notification    message from the subscription storage node, the notification message    including the requested subscription information associated with the    first UE. This requested information may be stored or used to update    the subscription information associated with the first UE at the    subscription control node. The received subscription information may    be bundled with subscription information associated with one or more    of the multiple UEs including the first UE.-   D5. Retrieving, from the requested subscription information for one    or more of the UEs and/or for the first UE, data representative of    the prefix address list associated with the first UE.-   D6. Transmitting, from the subscription control node, the requested    subscription information to the first DNS64 node, the subscription    information including data representative of the prefix address list    associated with the first UE.

FIG. 4a illustrates schematically a flow diagram of an example solutionof a process for use by a NAT64 node when interacting with the PCCarchitecture such as a policy or subscription control node (e.g. PCRFnode 101). The process for operating the NAT64 node in thecommunications network (e.g. communication network 100) including afirst UE. The NAT64 node includes a UE list of translation states forthe first UE, each translation state for use in translating IP addressesfrom a first type of IP address to a second type of IP address (e.g.from IPv6 to IPv4) for data packets received from or transmitted to thefirst UE. The steps performed by the NAT64 node, for each UE of themultiple UEs, may include:

-   E1. Receiving, at the NAT64 node, a data packet from a first UE, the    data packet having a first type of IP address (e.g. an IPv6    address).-   E2. Determining whether the first type of IP address corresponds to    a translation state in the translation state list for the first UE.    Proceeding to step E7 when the IP address of the data packet    corresponds to a translation state in the translation state list of    the first UE. Proceeding to step E3 when the IP address of the data    packet does not corresponds to a translation state in the    translation state list of the first UE.-   E3. Determining if the current number of translation states (CNTS)    in the translation state list of the first UE (e.g. UE list) is less    than a maximum number of translation states (MaxNTS) the NAT64 node    can allocate to the first UE. Proceeding to step E4 when the CNTS is    less than MaxNTS. Proceeding to step E8 when the CNTS is not less    than MaxNTS.-   E4. Creating a new translation state corresponding to the IP address    of the data packet and updating the translation state list for the    first UE.-   E5. Updating the CNTS to include the new translation state. This may    be implemented by incrementing the CNTS.-   E6. Transmitting, from the NAT64 node, an update message to the    subscription control node including an indication of the CNTS for    the first UE for use in tracking the total number of translation    states in use for the first UE. Additionally or alternatively,    transmitting the update message may occur after a predetermined    number of new translation states have been allocated to the first    UE. Additionally or alternatively, transmitting the update message    occurs periodically. Additionally or alternatively, transmitting the    update message occurs in response to receiving an update query from    the subscription control node. The update query from the    subscription control node may be sent periodically or when the    subscription control node requires an update of the translation    states used by each UE, or the number of unallocated translation    states, in the NAT64 node.-   E7. Translating the IP address of the data packet to a second type    of IP address. Proceed to step E1 for receiving further data packets    from the first UE and also other UEs.-   E8. Transmitting, from the NAT64 node, an error message associated    with the IP address of the received data packet to the first UE when    MaxNTS that the NAT64 node can allocate to the first UE has been    reached in the translation state list of the first UE. Proceed to    step E1 for receiving further data packets from the first UE and    other UEs.

When the connection established between the first UE and the IP addressassociated with a translation state in the translation state list forthe first UE is terminated, then the translation state is removed fromthe UE list. The CNTS for the first UE is also updated. This may beimplemented by decrementing the CNTS for the first UE.

FIG. 4b illustrates schematically another flow diagram associated withstep E2 for use by the NAT64 node for determining whether CNTS<MaxNTS.The steps performed by the NAT64 node, for each UE of the multiple UEs,may include:

-   F1. Determining whether the first type of IP address corresponds to    a translation state in the translation state list for the first UE.    Proceeding to step F2 for locating the subscription information    associated with the first UE.-   F2. Determining if the NAT64 node has the subscription information    associated with the first UE for use in retrieving the data    representative of the MaxNTS and CNTS for the first UE. If the    subscription information cannot be found or is not stored by the    NAT64 node, then proceed to step F3. Otherwise, proceed to step F5.-   F3. Sending a request query to the subscription control node for    subscription information associated with the first UE. The    subscription information may include the maximum translation states    the NAT64 node can allocate to the first UE.-   F4. Receiving, from the subscription control node, a response    message including subscription information of the first UE, the    subscription information further including the maximum number of    states that the NAT64 node can allocate to the first UE. The NAT64    may store or update the subscription information of the first UE.-   F5. Retrieving the MaxNTS that the NAT64 node can allocate to the    first UE from the stored or updated subscription information of the    first UE. Retrieving the and the CNTS from the stored or updated    subscription information for the first UE. If the subscription    information for the first UE does not include a CNTS for the first    UE, then the NAT64 node may initialise the CNTS for the first UE to    be zero.-   F6. Proceeding to perform step E3 using the retrieved MaxNTS and    CNTS for the first UE.

FIG. 4c illustrates schematically a further flow diagram of an exampleprocess for use by a NAT64 node for interacting with a subscriptioncontrol node (e.g. a PCRF node 101) for use in updating the subscriptioninformation associated with a first UE. The NAT64 node is in acommunication network including a first UE. The NAT64 node includes a UElist of translation states for the first UE, in which each translationstate is for use in translating IP addresses from a first type of IPaddress to a second type of IP address for data packets received from ortransmitted to the first UE. The NAT64 node may perform, for each ofmultiple UEs, the steps including:

-   G1. receiving a resource request message from the subscription    control node, the resource request message including a request for    the CNTS of a first UE, or for several or multiple UEs. The request    message may include an IP address associated with the first UE or    UE(s).-   G2. Retrieving the CNTS of the first UE or for several or multiple    UEs. The retrieval may be based on using the IP address associated    with each UE.-   G3. Transmitting, to the subscription control node, a notification    message including the CNTS for the first UE or the multiple UEs for    use by the subscription control node in monitoring and controlling    the NAT64 communication resources in the communication network.

FIG. 4d illustrates schematically yet another flow diagram of an exampleprocess for use by a NAT64 node in a communication network including afirst UE. The NAT64 node includes a UE list of translation states forthe first UE, in which each translation state is for use in translatingIP addresses from a first type of IP address to a second type of IPaddress for data packets received from or transmitted to the first UE.The communication network may include a second NAT64 node, the secondNAT64 node includes a second UE list of translation states for a firstUE. The NAT64 node may perform the steps including:

-   H1. Receiving a update message including subscription information of    the first UE. The subscription information of the first UE may    include a new MaxNTS that the NAT64 node can use when allocating    translation states to the first UE. The new MaxNTS may have been    derived by the subscription control node based on the CNTS of the UE    list associated with a first UE being served by the NAT64 node and a    second CNTS of a second UE list associated with the first UE being    served by the second NAT64 node.-   H2. Retrieving from the subscription information of the first UE the    MaxNTS that the NAT64 node can allocate to the first UE.-   H3. Updating the subscription information associated with the first    UE at the NAT64 node when the received MaxNTS is a new MaxNTS (i.e.    is different to the current MaxNTS for the first UE) that the NAT64    node can allocate to the first UE.

FIG. 5 illustrates schematically an example of a policy or subscriptioncontrol node 501, or a network node including PCC functionality (e.g.PCRF node 101), for use in implementing the methods, processes and/orthe solutions as described. The policy or subscription control node 501can be implemented as a combination of computer hardware and software,and can be configured to operate as an policy or subscription controlnode 501 in accordance with the solutions described above. Thesubscription control node 501 comprises a receiver 502, a transmitter503, a memory 504 and a processor 505, which are connected together. Thememory 504 stores the various programs/executable files that areimplemented by the processor 505 and also provides a storage unit forany required data e.g. data representative of subscription informationassociated with one or more UEs and data representative of translationstate lists for each of the one or more UEs, data representative ofpolicy rules for implementing a plurality of policies for monitoring andcontrolling one or more NAT64 nodes and/or one or more DNS64 nodes. Theprograms/executable files stored in the memory 504, and implemented byprocessor 505, include one or more of, but are not limited to, a UEsubscription information unit 506 and a UE policy control unit 507. TheUE subscription information unit 506 is for determining the subscriptioninformation associated with one or more UEs, the subscriptioninformation for each UE may include translation state usage informationassociated with one or more of the NAT64 nodes servicing thecorresponding UE(s). The UE policy control unit 507 may be a policyand/or analysis engine for monitoring and controlling one or more NAT64nodes and DNS64 nodes based on the UE subscription information.

In operation, the processor 505, receiver 502 and transmitter 503 areconfigured to collect translation state usage information from each ofthe NAT64 nodes. The processor 505 is configured to identify a set ofone or more UE(s) exceeding a maximum translation state usage allocatedto each of the multiple UEs based on the corresponding subscriptioninformation and the collected translation state usage information. Theprocessor 505 can also be configured to adjust the translation stateusage information in the subscription information of the identified setof UE(s) to meet the maximum translation state usage for each UE, andupdate the corresponding subscription information. The transmitter 503is further configured to transmit the updated subscription informationof the identified set of UE(s) to the corresponding NAT64 nodes servingthe identified set of UE(s).

The receiver may be configured to receive a request query from a firstNAT64 node of the multiple NAT64 nodes for subscription informationassociated with a first UE of the multiple UEs. In response, theprocessor may be configured to retrieve the subscription informationassociated with the first UE and the transmitter may be configured totransmit the subscription information associated with the first UE tothe first NAT64 node. The subscription information relates to NAT64 UEspecific subscription information and includes the maximum number oftranslation states that the first NAT64 node may allocate to the firstUE.

As the communication network further includes one or more DNS64 nodesthe receiver 502 is further configured to receive, from a DNS64 node, arequest for a prefix address list associated with a second UE of themultiple UEs for use in resolving a first type of IP address (e.g. IPv4address) with a second type of IP address (e.g. IPv6 address) for thesecond UE. The subscription information may also relate to DNS64 UEspecific subscription information and data representative of the prefixaddress list associated with one or more UE(s) such as the second UE.The processor 505 is configured to retrieve, from the subscriptioninformation for one or more of the UE(s), data representative of theprefix address list associated with the second UE. The transmitter isconfigured to transmit the data representative of the prefix addresslist associated with the second UE to the DNS64 node.

FIG. 6 illustrates schematically an example of a network node 601including the functionality of a NAT64 node, for use in implementing themethods, processes and/or the solutions as described. The network node601 can be implemented as a combination of computer hardware andsoftware, and can be configured to operate as an NAT64 node inaccordance with the solutions described above. The network node 601comprises a receiver 602, a transmitter 603, a memory 604 and aprocessor 605, which are connected together. The memory 604 stores thevarious programs/executable files that are implemented by the processor605 and also provides a storage unit for any required data e.g. datarepresentative of UE subscription information and UE translation statelists. A UE translation state list or UE list of translation states fora first UE includes translation states, each translation state for usein translating IP addresses from a first type of IP address (e.g. IPv6)to a second type of IP address (e.g. IPv4) for data packets receivedfrom or transmitted to the first UE.

In operation, the receiver 602 is configured for receiving a data packetfrom the first UE, the data packet having a first type of IP address.The processor 605 is configured for translating the IP address of thedata packet to a second type of IP address, when the IP address of thedata packet corresponds to a translation state in the UE list. Theprocessor 605 is further configured to determine if the current numberof translation states in the UE list is less than a maximum number oftranslation states the NAT64 node 601 can allocate to the first UE whenthe IP address does not correspond to a translation state in the UElist. If the current number of translation states is less than themaximum number of translation states allowable for the first UE, thenthe processor 605 is further configured to create a new translationstate corresponding to the IP address of the data packet and update theUE list when the current number of translation states is less than themaximum number of translation states. In addition, the processor 605 isconfigured to update the current number of translation states to includethe new translation state. The transmitter 603 is further configured totransmit an update message to the subscription control node including anindication of the current number of translation states for the first UEfor use in tracking the total number of translation states in use forthe first UE.

The communications network may include further NAT64 nodes, such as asecond NAT64 node, in which the second NAT64 node includes a second UElist of translation states for the first UE. The processor 605 andreceiver 602 are further configured to receive a message includingsubscription information of the first UE from the subscription controlnode, the subscription information including a new maximum number oftranslation states that the NAT64 node can allocate to the first UE, thenew maximum number of translation states having been derived from thecurrent number of translation states of the UE list and the currentnumber of translation states of the second UE list. The processor 605 isconfigured to update the maximum number of translation states of the UElist with the new maximum number of translation states.

Although the invention has been described in terms of example solutionsor preferred embodiments as set forth above, it should be understoodthat these examples or embodiments are illustrative only and that theclaims are not limited to only those examples or embodiments. Thoseskilled in the art will be able to make modifications and alternativesin view of the disclosure which are contemplated as falling within thescope of the appended claims. Each of the features, steps, or nodesdisclosed or illustrated in the present specification may beincorporated into the invention, whether alone or in any appropriatecombination with any other feature, step, or node disclosed orillustrated herein.

It will be appreciated by the person of skill in the art that variousmodifications may be made to the above described examples or embodimentsand/or one or more features of the described examples or embodiments maybe combined without departing from the scope of the present invention.

The invention claimed is:
 1. A method for operating a Policy andCharging Resource Function (PCRF) node in a communications network, thecommunications network including multiple user equipments, UEs, andmultiple network address translation 64, NAT64, nodes, the PCRF nodeincluding subscription information for one or more of the UEs, thesubscription information for each UE including translation state usageinformation associated with one or more of the NAT64 nodes servicingthat UE, wherein the subscription information is obtained from aSubscriber Policy Repository (SPR) node, the method comprising:collecting translation state usage information by receiving an updatemessage from each of the NAT64 nodes, the update message indicating acurrent number of translation states each Nat64 node has allocated toeach UE serviced by that NAT64 node; identifying a set of one or moreUE(s) exceeding a maximum translation state usage allocated to each ofthe multiple UEs based on the corresponding subscription information andthe collected translation state usage information; adjusting thetranslation state usage information in the subscription information ofthe identified set of UE(s) to meet the maximum translation state usagefor each UE, and updating the corresponding subscription information;and transmitting the updated subscription information of the identifiedset of UE(s) to the corresponding NAT64 nodes.
 2. The method as claimedin claim 1, wherein the step of collecting translation usage informationfurther includes calculating, for each UE, a total number of translationstates allocated to said each UE from the collected translation stateusage information.
 3. The method as claimed in claim 2, wherein the stepof identifying the set of UE(s) further comprises including an second UEin the set of UE(s) when the total number of translation states for thesecond UE exceeds the maximum number of translation states allocated tothe second UE.
 4. The method as claimed in claim 1, wherein the step ofadjusting the translation state usage information in the subscriptioninformation of the identified set of UE(s) further comprises adjustingthe maximum number of translation states for each UE in the set of UE(s)that the corresponding NAT64 nodes can allocate for said each UE.
 5. Themethod as claimed in claim 1, further comprising the steps of: receivinga request query from a first NAT64 node of the multiple NAT64 nodes forsubscription information associated with a first UE of the multiple UEs;and transmitting the subscription information associated with the firstUE to the first NAT64 node, the subscription information including themaximum number of translation states that the first NAT64 node mayallocate to the first UE.
 6. The method as claimed in claim 1, furthercomprising the steps of: transmitting a request query to the SPR nodefor subscription information associated with one or more of the multipleUEs; and receiving and storing the subscription information associatedwith the one or more of the multiple UEs.
 7. The method as claimed inclaim 1, wherein the communication network further comprises a DomainName System, DNS, 64 node, the method including the steps of: receiving,from the DNS64 node, a request for a prefix address list associated witha third UE of the multiple UEs for use in resolving a first type ofInternet Protocol (IP) address with a second type of IP address used inservices requested by the third UE, retrieving, from the subscriptioninformation for one or more of the UEs, data representative of theprefix address list associated with the third UE; and retrieving, fromthe subscription information for one or more of the UEs, datarepresentative of the prefix address list associated with the third UE;and transmitting the data representative of the prefix address listassociated with the third UE to the DNS64 node.
 8. The method as claimedin claim 7, wherein the step of retrieving further comprises:transmitting a request query to the SPR node for subscriptioninformation associated with the third UE; receiving and storing thesubscription information associated with the third UE; and retrievingfrom the subscription information associated with the third UE the datarepresentative of the prefix address list associated with the third UE.9. The method as claimed in claim 1, further comprising transmitting thesubscription information for the one or more of the UE(s) to associatedNAT64 nodes.
 10. The method as claimed in claim 1, further comprisingtransmitting the updated subscription information to the SPR node, theupdated subscription information including adjusted translation stateusage information for one or more UE(s).
 11. The method or node asclaimed in claim 1, wherein a first type of Internet Protocol (IP)address is an IP version 6, IPv6, address and a second type of IPaddress is an IP version 4, IPv4, address.
 12. A Policy and ChargingResource Function (PCRF) node for use in a communications network, thecommunications network including multiple user equipments, UEs, andmultiple network address translation 64, NAT64, nodes, the PCRF nodecomprising: a receiver, a transmitter, a memory unit, and processor, theprocessor being connected to the receiver, to the transmitter, and tothe memory unit, wherein the memory unit includes storage forsubscription information for one or more of the UEs, the subscriptioninformation for each UE including translation state usage informationassociated with one or more of the NAT64 nodes servicing the UE, whereinthe subscription information is obtained from a Subscriber PolicyRepository (SPR) node, wherein: the processor and transmitter areconfigured to collect translation state usage information by receivingan update message from each NAT64 node, the update message indicating acurrent number of translation states each NAT64 node has allocated toeach UE serviced by that Nat64 node; the processor is further configuredto: identify a set of one or more UE(s) exceeding a maximum translationstate usage allocated to each of the multiple UEs based on thecorresponding subscription information and the collected translationstate usage information; and adjust the translation state usageinformation in the subscription information of the identified set ofUE(s) to meet the maximum translation state usage for each UE, andupdating the corresponding subscription information; and the transmitteris further configured to transmit the updated subscription informationof the identified set of UE(s) to the corresponding NAT64 nodes.
 13. ThePCRF node as claimed in claim 12, wherein the processor, receiver andtransmitter are further configured to: receive a request query from afirst NAT64 node of the multiple NAT64 nodes for subscriptioninformation associated with a first UE; retrieve the subscriptioninformation associated with the first UE; and transmit the subscriptioninformation associated with the first UE to the first NAT64 node, thesubscription information including the maximum number of translationstates that the first NAT64 node may allocate to the first UE.
 14. ThePCRF node as claimed in claim 12, wherein the communication networkfurther comprises a Domain Name System, DNS, 64 node, and the processor,transmitter and receiver are further configured to: receive, from theDNS64 node, a request for a prefix address list associated with a secondUE of the multiple UEs for use in resolving a first type of InternetProtocol (IP) address with a second type of IP address for the secondUE; retrieve, from the subscription information for one or more of theUEs, data representative of the prefix address list associated with thesecond UE; and transmit the data representative of the prefix addresslist associated with the second UE to the DNS64 node.
 15. Anon-transitory computer readable storage medium having stored thereon aset of computer executable instructions to be executed by a processor ofa Policy and Charging Resource Function (PCRF) node in a communicationsnetwork, the communications network including multiple user equipments,UEs, and multiple network address translation 64, NAT64, nodes, the PCRFnode including subscription information for one or more of the UEs, thesubscription information for each UE including translation state usageinformation associated with one or more of the NAT64 nodes servicingthat UE, wherein the subscription information is obtained from aSubscriber Policy Repository (SPR) node, the set of computer executableinstructions when executed by the processor of the PCRF node causes theprocessor to perform operations comprising: collecting translation stateusage information by receiving an update message from each of the NAT64nodes, the update message indicating a current number of translationstates each NAT64 node has allocated to each UE serviced by that NAT64node; identifying a set of one or more UE(s) exceeding a maximumtranslation state usage allocated to each of the multiple UEs; adjustingthe translation state usage information in the subscription informationof the identified set of UE(s) to meet the maximum translation stateusage for each UE, and updating the corresponding subscriptioninformation; and transmitting the updated subscription information ofthe identified set of UE(s) to the corresponding NAT64 nodes.